Forecasters left scratching their heads over Sandy

There is no precedent for a vast tropical system to strike this far north so late in the season.

There is no precedent for a vast tropical system to strike this far north so late in the season.

Moving from east to west in a highly anomalous track, Sandy brought surging tropical conditions inland, where it collided with polar air to create an unprecedented "superstorm."

Energized by a jet stream feeding off spectacular temperature contrasts between wintertime air and subtropical Gulf Stream waters flowing from the Caribbean Sea to northern Europe, there would be no modern analog for meteorologists to study prior to making storm surge and wind forecasts.

Sandy's already enormous circulation had expanded to cover a 1,500-mile wide area from Canada to Florida, which resembled a satellite image from the dire 2004 film "The Day After Tomorrow."

Hurricanes normally weaken rapidly as they move inland, and away from the fuel of warm water. But not with Sandy.

The storm was strengthened by an enormous reservoir of wind energy that infused the fast-approaching Category 1 hurricane, making it a true hybrid storm, dubbed "Frankenstorm" by NOAA.

Locally, extensive tree damage and subsequent power outages proved to be far greater than what we have experienced in storms with comparably predicted 50-70 mph winds.

In the summer, we call these microbursts or downbursts (straight-line damaging wind events), which are much more powerful and potentially devastating in narrow corridors than the already gusty storm winds.

For a time on Monday, a weak temperature inversion held hurricane-force winds a few thousand feet aloft.

But as forecasters warned, the vertical dam of air eventually gave way between 6 p.m. Monday and 2 a.m. Tuesday.

The downward rush of air came, not all at once, but in thundering waves at varying intervals, as the atmosphere "overturned" with great force.

As awful as the damage was in the Poconos, it could have been even worse.

Southern Pennsylvania and New Jersey experienced far more structural damage to homes and businesses than areas to the north.

Yet, our rugged, hilly and more wooded terrain contributed to the disproportionate tree damage and power outages.

The near-historic low pressure (28.56 inches) — just shy of the "Storm of the Century" March 1993 blizzard (28.50 inches) — accounted for the huge extent and prolonged duration of the strong winds.

The only storms to produce higher winds in the Poconos were the Great Appalachian Storm in November 1950 (76 mph in Stroudsburg, and nearly 90 mph in the mountains), and the northward passage of Hurricane Hazel in October 1954.